I read that abstract and didn't see any specific way of differentiating, since it doesn't mention a new test, while the other pages indicated that etg readings may differ by large factors for different people with equal consumption and time, while much higher etg readings can appear from mouthwash, etc., in addition to the hand sanitizer (which produced higher readings from inhalation in the other studies mentioned, not from absorption in the skin, contra this abstract). The makers of the test specifically said that it should not be used for legal purposes, because it does not constitute proof of drinking. Instead, polygraphs and so forth, including falsely certain statements ("we know that you have been drinking and it is best that you admit it so that we can help you," etc.), should be used to get confessions, according to that website.